Bone Cyst In Foot

Okay, so I got the results of a recent MRI back today. We were looking to see what was going on with my ankle, but the findings in my foot have so far been the most fascinating. In one of the bones in my foot I have a decent sized bone cyst near the end of the bone. He showed me it and I could see it very clearly on the MRI, just a big hollow looking space in the end of the bone.

He didn't seem super concerned, but I am a bit. I've never heard of a bone cyst before and am wondering what exactly causes them and if I should worry? Is it possible it can be cancerous? Or are these usually just benign growths in the bone?